Butyrolactone is a chemical having wide application and is conventionally used as a solvent for polymers, fluorinated hydrocarbons, shellac and cellulose triacetate. Its solvent properties also make it useful in paint removers, petroleum processing and in the selective extraction of water immiscible alcohols. The compound also finds application as a chemical intermediate for monoazo dye stuffs and as an agricultural chemical adjuvant in herbicidal, fungidical, insecticidal and plant growth regulator formulations.
Generally, butyrolactone is produced by various processes involving high pressure synthesis from acetylene and formaldehyde. These processes are capable of producing a substantially pure product which is further purified by subjecting the crude product to fractional distillation. However, it has been found that butyrolactone purified by distillation through a fractionating column is not color stable on standing at ambient temperature and undergoes significant coloration at temperatures above about 20.degree. C. Also, in acid formulations, butyrolactone develops an objectionable dark color which inhibits its use in certain dyestuffs and photosensitive emollients. Various processes have been proposed to reduce product degradation including expensive and time consuming extractions, multiple washings, etc.
Accordingly it is an object of this invention to provide an economical and commercially feasible butyrolactone purification process which maximizes color stability at ambient and elevated temperatures in acid or basic media.